Keep doing each step manually, and see where it slips up:
−7.9+8.2−3.4+2.1=−1
−7.9+8.2+(−3.4)+2.1=−1
−7.9+(−3.4)+8.2+2.1=−1
(−7.9+(−3.4))+(8.2+2.1)=−1
−11.3+10.3=−1
There are 4 teams in total and each team has 7 members. One of the team will be the host team.
Tournament committee will be made from 3 members from the host team and 2 members from each of the three remaining teams. Selecting the members for tournament committee is a combinations problem. We have to select 3 members out 7 for host team and 2 members out of 7 from each of the remaining 3 teams.
So total number of possible 9 member tournament committees will be equal to:

This is the case when a host team is fixed. Since any team can be the host team, there are 4 possible ways to select a host team. So the total number of possible 9 member tournament committee will be:

Therefore, there are 2917215 possible 9 member tournament committees
The answer is B) <span>(q - 2)(2p - 5r)
</span>2pq - 5qr + 10r - 4p = 2pq - 4p - 5qr + 10r
= 2pq - 4p - (5qr - 10r)
= 2p(q - 2) - 5r(q - 2)
= (q - 2)(2p - 5r)
The answer to this question is two hundred and eighty